Coil module, electronic device, and wireless charging system

Abstract

The present application relates to the technical field of wireless charging, and provides a coil module, an electronic device, and a wireless charging system, used to solve the problem of the excessive thickness of a wireless charging coil module adversely affecting the arrangement of other functional devices within an electronic device. The coil module comprises a coil structure. The coil structure comprises a functional layer, and along the direction of thickness of the coil structure, the functional layer comprises a first wiring sub-layer, a second wiring sub-layer, and an insulating sub-layer located between the first wiring sub-layer and the second wiring sub-layer. The coil structure further comprises a first end, a second end, and a plurality of coil groups connected in series in sequence. The first end and the plurality of coil groups are disposed in the first wiring sub-layer, and the outermost coil group is connected to the first end. The second end is disposed in the second wiring sub-layer. The insulating sub-layer is provided with a via, and a connection structure is disposed within the via. The innermost coil group is connected to the second end by means of the connection structure within the insulating sub-layer, so that the first end is electrically connected to the second end by means of the plurality of coil groups connected in series in sequence.

Description

Coil module, electronic device and wireless charging system

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on January 11, 2024, with application number 202410047758.4 and application name “Coil module, electronic device and wireless charging system”, and the Chinese patent application filed with the State Intellectual Property Office of China on March 6, 2024, with application number 202410255807.3 and application name “Coil module, electronic device and wireless charging system”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of wireless charging technology, and in particular to a coil module, an electronic device, and a wireless charging system. Background Art

[0003] Because wireless charging is safer, more reliable, and easier to use than wired charging, more and more electronic devices, such as mobile phones, tablets, and smart watches, are adopting wireless charging technology. A key component in implementing wireless charging technology is the wireless charging coil module.

[0004] However, existing wireless charging coil modules are relatively thick. This hinders the placement of functional components within electronic devices, such as those supporting biometrics, high-quality imaging, and artificial intelligence, as they increasingly incorporate advanced features (e.g., biometrics, high-quality imaging, and artificial intelligence). Addressing this issue is a pressing need. Summary of the Invention

[0005] In order to solve the above technical problems, the present application provides a coil module, an electronic device and a wireless charging system to solve the problem that the thickness of the wireless charging coil module in the prior art is relatively thick, which is not conducive to the arrangement of other functional components in the electronic device.

[0006] In the first aspect, an embodiment of the present application provides a coil module, which includes: a coil structure; the coil structure includes a functional layer, and along the thickness direction of the coil structure, the functional layer includes a first wiring sublayer, a second wiring sublayer and an insulating sublayer located between the first wiring sublayer and the second wiring sublayer; the coil structure also includes a first end, a second end and a plurality of coil groups connected in series in sequence, the first end and the plurality of coil groups are arranged in the first wiring sublayer, and the coil group in the outermost circle is connected to the first end; the second end is arranged in the second wiring sublayer; a via is provided on the insulating sublayer, and a connecting structure is provided in the via; the coil group in the innermost circle is connected to the second end through the connecting structure in the insulating sublayer, so that the first end is electrically connected to the second end through the plurality of coil groups connected in series in sequence.

[0007] In the present application, multiple coil groups occupying a larger area are arranged on the first wire sub-layer, and the second wiring sub-layer only includes the second end occupying a smaller area. In this way, when the coil module is set in the electronic device, other wiring of the electronic device can be set on the second wiring sub-layer to avoid other wiring occupying the internal space of the electronic device, which is conducive to the arrangement of other structures. Alternatively, since the second wiring sub-layer only has the second end occupying a smaller area, the second end occupying a smaller area can be embedded in other structures of the electronic device, so that the coil module occupies less space inside the electronic device, which is conducive to the arrangement of other structures.

[0008] For example, the thickness direction of the coil structure can be the thickness direction of the electronic device, or the direction of the central axis passing through the centers of the multiple coil groups. The thickness direction of the coil structure is perpendicular to the first wiring sublayer, the second wiring sublayer, and the insulating sublayer.

[0009] According to the first aspect, the coil module further includes: a magnetic conductive layer; the magnetic conductive layer includes a hollow portion, and the second end is disposed in the hollow portion.

[0010] The provision of the magnetic conductive layer can concentrate the magnetic field, increase the coil inductance of the coil module, and can also shield part of the magnetic field, reducing the eddy current loss generated by the magnetic field on some structures of the electronic device (such as the middle frame, battery, printed circuit board, etc.). In addition, by embedding the second end of the coil structure in the magnetic conductive layer, the second end can be avoided from occupying the thickness direction of the coil module, reducing the thickness of the coil module, and making the thickness of the wireless charging coil extremely thin, which is extremely advantageous in terms of thickness. For example, the thickness of the coil module is less than 0.2mm. For example, the thickness of the coil module is only 0.1Xmm (where X is 1, 2, 3, 4, 5, 6, 7, 8, 9, etc., that is, the thickness of the coil module is only 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.17mm, 0.18mm or 0.19mm). Of course, it can also be less than 0.1mm.

[0011] According to the first aspect, or any implementation of the first aspect above, along the thickness direction of the coil structure, the magnetic conductive layer includes a first protective sublayer, a second protective sublayer and a magnetic conductive sublayer located between the first protective sublayer and the second protective sublayer, and the magnetic conductive sublayer includes multiple layers of adhesive and nanocrystals located between two adjacent layers of adhesive; the first protective sublayer is arranged adjacent to the coil structure, and the adhesive arranged adjacent to the second protective sublayer is the first adhesive; the first protective sublayer, other adhesives except the first adhesive and the film layer where the nanocrystals are located are provided with a first opening, and the film layer where the first adhesive and the second protective sublayer are located is provided with a second opening, and the first opening and the second opening form a hollow portion; the projection of the second opening on the reference plane is located within the projection of the first opening on the reference plane, and the reference plane is perpendicular to the thickness direction of the coil structure.

[0012] The openings of the first adhesive and the second protective sublayer are made smaller, that is, the first adhesive and the second protective sublayer extend partially toward the edge of the hollow portion, so that the nanocrystalline powder can be prevented from falling out, making the structure of the coil module more reliable.

[0013] Exemplarily, the reference plane is parallel to the first wiring sub-layer, and other film layers in the coil module are parallel to each other.

[0014] Exemplarily, the magnetic conductive sublayer includes three layers of adhesive and two layers of nanocrystals located between two adjacent layers of adhesive.

[0015] According to the first aspect, or any implementation of the first aspect above, the coil structure further includes a flexible circuit board unit; the flexible circuit board unit is located in a preset area of ​​the second wiring sublayer, and the preset area is an area in the second wiring sublayer where no second end is provided.

[0016] That is to say, when the coil module is provided in an electronic device, the flexible circuit board in the electronic device can be provided in the second wiring sublayer, that is, the coil module includes both the wireless charging coil and the flexible circuit board in the electronic device. In this way, the internal space of the electronic device is avoided from being occupied by other flexible circuit boards, which is conducive to the setting of other structures and can also reduce the process steps.

[0017] According to the first aspect, or any implementation of the first aspect above, the preset area includes a first sub-area, and the first sub-area is an area formed by the projection of the outermost coil group on the second wiring sub-layer extending by a first preset length in all directions; when the line width of the flexible circuit board unit in the first sub-area is greater than the second preset length, the routing of the flexible circuit board unit in the first sub-area is cut into multiple lines.

[0018] That is, the wider traces of the flexible circuit board unit in the first sub-region are cut into multiple thin lines, thereby avoiding excessive eddy current loss on the wider traces.

[0019] For example, the first preset length may be 5 mm, and the second preset length may be 8 mm.

[0020] According to the first aspect, or any implementation of the first aspect above, the coil module further includes: a magnetic conductive layer; along the thickness direction of the coil structure, the magnetic conductive layer is located on a side of the second wiring sublayer away from the first wiring sublayer.

[0021] The magnetic conductive layer is arranged on the side of the second wiring sublayer away from the first wiring sublayer, that is, the first wiring sublayer including the coil group is placed away from the nanocrystal side, which is conducive to improving the mutual inductance and improving the wireless charging performance.

[0022] Of course, the magnetic conductive layer may also be located on the side of the first wiring sub-layer away from the second wiring sub-layer.

[0023] According to the first aspect, or any implementation of the first aspect above, the number of coil groups is N, where N is less than or equal to 8 and greater than or equal to 7.

[0024] This arrangement enables the coil structure to achieve both high-power and high-freedom wireless charging effects.

[0025] Exemplarily, the number of coil groups is 7 or 8, and of course, it can also be 7.5 or the like.

[0026] According to the first aspect, or any implementation of the first aspect above, the number of coil groups is 7, the thickness of the first wiring sublayer is greater than or equal to 25μm and less than or equal to 40μ, and each coil group includes M strands of wire, where M is greater than or equal to 3.

[0027] With this arrangement, even if the coil assembly is thick, large eddy current losses can be avoided in the thicker coil assembly.

[0028] Exemplarily, M is 4.

[0029] According to the first aspect, or any implementation of the first aspect above, the number of coil groups is 7, the thickness of the first wiring sublayer is less than or equal to 25 μm, and each coil group includes M strands of wire, where M is less than or equal to 4.

[0030] Because the M strands of wire are formed by cutting and routing, when M is less than or equal to 4, it can avoid wasting a lot of routing space and can also have a better flow effect.

[0031] Exemplarily, M is 3.

[0032] According to the first aspect, or any implementation of the first aspect above, the number of coil groups is 8, the thickness of the first wiring sublayer is greater than or equal to 25μm and less than or equal to 40μ, and each coil group includes M strands of wire, where M is greater than or equal to 2.

[0033] This arrangement can avoid large eddy current losses in thicker coil groups even if the coil groups are thicker, and will not increase impedance due to the increase in the number of coil groups.

[0034] Exemplarily, M is 3.

[0035] According to the first aspect, or any implementation of the first aspect above, the number of coil groups is 8, the thickness of the first wiring sublayer is less than or equal to 25 μm, and each coil group includes M strands of wire, where M is less than or equal to 3.

[0036] Because the M strands of wire are formed by cutting and routing, when M is less than or equal to 4, it can avoid wasting a lot of routing space and can also achieve a better current flow effect. Moreover, the impedance will not increase due to the increase in the number of coil groups.

[0037] Exemplarily, M is 3.

[0038] According to the first aspect, or any implementation of the first aspect above, the widths of the multiple coil groups gradually increase in a direction away from the center of the coil structure, so that the current distribution is more uniform.

[0039] Exemplarily, there are eight coil groups, and from the innermost to the outermost coil groups, the coil groups are the first coil group, the second coil group, the third coil group, the fourth coil group, the fifth coil group, the sixth coil group, the seventh coil group, and the eighth coil group. The gradually increasing widths of the multiple coil groups can mean that the widths of the first coil group, the second coil group, the third coil group, the fourth coil group, the fifth coil group, the sixth coil group, the seventh coil group, and the eighth coil group increase in sequence. The gradually increasing widths of the multiple coil groups can also mean that some adjacent coil groups in the eight coil groups have the same width, and the widths of coil groups with different widths gradually increase as they move away from the center of the coil structure. For example, the first coil group and the second coil group have the same widths, the third coil group, the fourth coil group, and the fifth coil group have the same widths, and the sixth coil group, the seventh coil group, and the eighth coil group have the same widths, and the widths of the first coil group, the third coil group, and the sixth coil group increase in sequence. For another example, the third coil group, the fourth coil group, and the fifth coil group have the same widths, the sixth coil group and the seventh coil group have the same widths, and the widths of the first coil group, the second coil group, the third coil group, the sixth coil group, and the eighth coil group increase in sequence.

[0040] Exemplarily, the number of strands in each coil group may be the same, such as 3 strands or 4 strands.

[0041] According to the first aspect, or any implementation of the first aspect above, the number of coil groups is N, and the N coil groups include L internal coil groups and (NL) external coil groups arranged around the L internal coil groups; each coil group includes multiple strands of wire; the number of wire strands located in the external coil group is greater than the number of wire strands located in the internal coil group.

[0042] This arrangement makes the current distribution more uniform.

[0043] Exemplarily, the number of coil groups is N, and the coil groups from the innermost circle to the outermost circle are the first coil group, the second coil group, the third coil group, the fourth coil group, the fifth coil group, the sixth coil group, the seventh coil group, and the eighth coil group. The fifth coil group, the sixth coil group, the seventh coil group, and the eighth coil group have the same number of strands, the first coil group, the second coil group, the third coil group, and the fourth coil group have the same number of strands, and the eighth coil group has a larger number of strands than the first coil group; alternatively, the second coil group, the third coil group, the fourth coil group, the fifth coil group, the sixth coil group, the seventh coil group, and the eighth coil group have the same number of strands, the fourth coil group and the fifth coil group have the same number of strands, the first coil group, the second coil group, and the third coil group have the same number of strands, the eighth coil group has a larger number of strands than the fifth coil group, and the fifth coil group has a larger number of strands than the first coil group.

[0044] According to the first aspect, or any implementation of the first aspect above, the coil structure is an FPC coil.

[0045] The FPC coil has good flatness and is relatively thin, which further facilitates the lightweight design of equipment using the coil module.

[0046] In a second aspect, an embodiment of the present application provides an electronic device, comprising: the coil module of the first aspect and any one of the first aspect.

[0047] The second aspect corresponds to the first aspect and any implementation of the first aspect. The technical effects corresponding to the second aspect can be referred to the technical effects corresponding to the first aspect and any implementation of the first aspect, and will not be repeated here.

[0048] According to the second aspect, the coil structure also includes at least one flexible circuit board unit; the flexible circuit board unit is located in a preset area of ​​the second wiring sublayer, and the preset area is an area in the second wiring sublayer where no second end is provided; the electronic device also includes a printed circuit board, and the flexible circuit board unit is connected to the printed circuit board.

[0049] The flexible circuit board connected to the printed circuit board in the electronic device can be placed on the second wiring sublayer, that is, the coil module includes both the wireless charging coil and the flexible circuit board in the electronic device. In this way, other flexible circuit boards are avoided from occupying the internal space of the electronic device, which is conducive to the arrangement of other structures and can also reduce the process steps.

[0050] For example, only one flexible circuit board connected to the printed circuit board in the electronic device can be arranged in the second wiring sublayer, two flexible circuit boards connected to the printed circuit board in the electronic device can be arranged in the second wiring sublayer, and multiple (such as three or more) flexible circuit boards connected to the printed circuit board in the electronic device can be arranged in the second wiring sublayer.

[0051] According to the second aspect, or any implementation of the second aspect above, the printed circuit board includes a main board and a sub-board, and the main board is connected to the sub-board through a flexible circuit board unit.

[0052] That is, setting the flexible circuit board connecting the main board and the sub-board on the second wiring sub-layer can reduce the occupation of the internal space of the electronic device by the flexible circuit board compared to setting the flexible circuit board connecting the main board and the sub-board in the accommodation space of the electronic device, which is conducive to the setting of other structures.

[0053] According to the second aspect, or any implementation of the second aspect above, the electronic device further includes a functional device, and the functional device is connected to the printed circuit board through the flexible circuit board unit.

[0054] That is, setting the flexible circuit board connecting the functional devices and the printed circuit board on the second wiring sublayer can reduce the occupation of the internal space of the electronic device by the flexible circuit board, compared with setting the flexible circuit board connecting the functional devices and the printed circuit board in the accommodation space of the electronic device, which is conducive to the setting of other structures.

[0055] Exemplarily, the functional device includes a speaker or a SIM card. Of course, the functional device is not limited thereto.

[0056] According to the second aspect, or any implementation of the second aspect above, the flexible circuit board unit is configured as an NFC coil. That is, the NFC coil is configured on the second wiring sublayer. Compared to configuring the NFC coil within the storage space of the electronic device, this can reduce the internal space occupied by the flexible circuit board in the electronic device, facilitating the configuration of other structures.

[0057] According to the second aspect, or any implementation of the second aspect above, the electronic device includes a wireless charging receiving device or a wireless charging transmitting device. Specifically, the receiving coil of the wireless charging receiving device may be the coil module of the first aspect or any one of the first aspects, and / or the transmitting coil of the wireless charging transmitting device may be the coil module of the first aspect or any one of the first aspects.

[0058] In a third aspect, an embodiment of the present application provides a wireless charging system, which includes: the second aspect and the electronic device of any one of the second aspect.

[0059] The third aspect corresponds to the second aspect and any implementation of the second aspect. The technical effects corresponding to the third aspect and any implementation of the third aspect can be referred to the technical effects corresponding to the above-mentioned second aspect and any implementation of the second aspect, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] FIG1 is a schematic structural diagram of a wireless charging system provided in an embodiment of the present application;

[0061] FIG2 is a schematic diagram of a circuit structure of a wireless charging system provided in an embodiment of the present application;

[0062] FIG3 is a schematic structural diagram of the wireless charging receiving device shown in FIG1 ;

[0063] FIG4 is a film layer diagram of a coil module provided in Example 1 of the present application;

[0064] FIG5a is a perspective view of a coil module provided in Example 1 of the present application;

[0065] FIG5b is a plan view of the coil module shown in FIG5a;

[0066] FIG5c is an exploded view of the coil structure in the coil module shown in FIG5a;

[0067] FIG5 d is an exploded view of the coil module shown in FIG5 a ;

[0068] FIG6 is an exploded view of another coil module provided in Example 1 of the present application;

[0069] FIG7 is an exploded view of another coil module provided in Example 1 of the present application;

[0070] FIG8 is an exploded view of another coil module provided in Example 1 of the present application;

[0071] FIG9 is a simulation diagram of current density distribution on a coil module provided in Example 1 of the present application;

[0072] FIG10 is a simulation diagram of current density distribution on another coil module provided in Example 1 of the present application;

[0073] FIG11 is a simulation diagram of current density distribution on another coil module provided in Example 1 of the present application;

[0074] FIG12 is a film layer diagram of a coil module provided in Example 2 of the present application;

[0075] FIG13 is a plan view of a coil module provided in Example 2 of the present application;

[0076] FIG. 14 is an exploded view of the coil module shown in FIG. 13 . DETAILED DESCRIPTION

[0077] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0078] The term "and / or" in this article is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0079] In the description and claims of the embodiments of this application, the terms "first" and "second" are used to distinguish different objects, rather than to describe a specific order of objects. For example, the terms "first target object" and "second target object" are used to distinguish different objects, rather than to describe a specific order of objects.

[0080] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0081] In the description of the embodiments of this application, unless otherwise specified, "multiple" means two or more. For example, "multiple processing units" means two or more processing units; "multiple systems" means two or more systems.

[0082] The connection relationships described in this application refer to direct or indirect connections. For example, the connection between A and B can be either a direct connection between A and B or an indirect connection between A and B via one or more other electrical components. For example, A and C can be directly connected, and C can be directly connected to B, so that A and B are connected through C. It is also understandable that the description of "A connecting to B" in this application can be a direct connection between A and B or an indirect connection between A and B via one or more other electrical components.

[0083] First, the terms involved in this application are explained:

[0084] Layers refer to the number of planes in which the wires contained in the coils provided by this application are arranged. When all the wires contained in a coil are wound on the same plane to form a planar coil, the coil is considered a single-layer coil. When all the wires contained in a coil are not arranged on the same plane, for example, the first wire is wound on a first planar layer and the second wire is wound on a second planar layer, and the first and second wires are connected through vias in the insulating layer between the first and second planar layers, the coil is considered a two-layer coil.

[0085] The number of turns refers to the number of turns of the wire winding in each coil.

[0086] The number of strands refers to the number of parallel wires in each turn of the coil when the coil is wound.

[0087] Next, the technical scenarios involved in the embodiments of the present application are described.

[0088] The technical solution of the present application is applied to the wireless charging technology scenario. The scenario includes a wireless charging device and a device to be charged. Among them, the wireless charging device is used to charge the device to be charged with a wireless charging function. For example, the wireless charging device can be a wireless charging mobile power supply, a wireless charging plate, a wireless charger, etc., and the device to be charged can be a mobile phone, a tablet, a laptop computer, a personal digital assistant (PDA for short), a car computer, a smart wearable device (such as a smart watch, a smart bracelet, headphones, etc.), virtual reality (VR), augmented reality (AR) and other electronic devices. The above-mentioned device to be charged can also be a wireless charging electric car, a wireless charging household appliance (such as a sweeping robot, etc.), a drone and other electronic products. For another example, the wireless charging device can be a tablet computer, a laptop computer, a mobile phone, etc., and the device to be charged can be a stylus, a magnetic keyboard, etc.

[0089] The wireless charging device mentioned above may also be referred to as a wireless charging transmitting device, and the device to be charged may also be referred to as a wireless charging receiving device.

[0090] To help those skilled in the art better understand the technical solutions provided by the embodiments of this application, the following briefly introduces the principles of wireless charging in a wireless charging technology scenario. This description is based on an example in which the wireless charging transmitter is a wireless charger and the wireless charging receiver is a mobile phone. The rest of the following description is also based on an example in which the wireless charging transmitter is a wireless charger and the wireless charging receiver is a mobile phone.

[0091] Refer to Figure 1, which is a schematic diagram of the structure of a wireless charging system provided in an embodiment of the present application. As shown in Figure 1, wireless charging system 01 includes a wireless charging transmitter 10 and a wireless charging receiver 20. Wireless charging transmitter 10 can be a wireless charger, and wireless charging receiver 20 can be a mobile phone. The wireless charger performs wireless charging for the mobile phone.

[0092] It should be noted that the wireless charger shown in Figure 1 has a certain inclination so that the mobile phone can lean against the wireless charger. Of course, this does not constitute a limitation of the present application. In other optional embodiments of the present application, the wireless charger can also have other forms, for example, the wireless charger is flat and supports the mobile phone to be placed horizontally on it.

[0093] 2 , which is a schematic diagram of a circuit structure of a wireless charging system according to an embodiment of the present application. As shown in FIG2 , a wireless charging transmitting device 10 includes a power supply 11 and a wireless transmitting device 12 .

[0094] The power supply 11 is used to provide a DC voltage. In order to distinguish it from other DC voltages, the DC voltage provided by the power supply 11 is a first DC voltage.

[0095] The wireless transmitting device 12 includes a direct current (DC) / alternating current (AC) circuit 122 , a resonant capacitor C1 , and a transmitting coil L1 .

[0096] In some embodiments, the wireless transmitting device 12 further includes a voltage conversion circuit 121. The voltage conversion circuit 121 is electrically connected to the power supply 11 and is configured to convert a first DC voltage output by the power supply 11 into a stable second DC voltage. Exemplarily, the voltage conversion circuit 121 may be a boost circuit (e.g., a boost circuit, a boost transformer, or a power amplifier) ​​configured to boost the first DC voltage output by the power supply 11 before outputting it.

[0097] When the voltage conversion circuit 121 is a boost circuit, it can increase the potential difference between the wireless charging transmitting device 10 and the wireless charging receiving device 20, thereby improving the energy transfer capability of the system and facilitating high-power transmission.

[0098] Of course, the voltage conversion circuit 121 is not limited to a boost circuit, and can also be a buck circuit for outputting the first DC voltage output by the power supply 11 after stepping down the voltage. Those skilled in the art can configure the voltage conversion circuit 121 according to actual conditions.

[0099] The DC / AC circuit 122 is electrically connected to the voltage conversion circuit 121 and is configured to convert the second DC voltage output by the voltage conversion circuit 121 into AC power. For example, the DC / AC circuit 122 may be an inverter bridge, and its circuit structure may be a full-bridge circuit or a half-bridge circuit. The DC / AC circuit 122 is also referred to as a transmit (TX) chip.

[0100] Resonant capacitor C1 and transmitting coil L1 are connected in series to form a series resonant network. Transmitting coil L1 is electrically connected to DC / AC circuit 122 via resonant capacitor C1. As DC / AC circuit 122 charges and discharges resonant capacitor C1 and transmitting coil L1, transmitting coil L1 can convert alternating current into an alternating magnetic field.

[0101] In conjunction with Figure 3, Figure 3 is a schematic structural diagram of the wireless charging receiving device shown in Figure 1. As shown in Figure 3, the wireless charging receiving device 20, such as a mobile phone, includes a rear shell 201, a display screen 202 and a middle frame 203. The display screen 202 and the rear shell 201 are respectively located on both sides of the middle frame 203. The rear shell 201, the display screen 202 and the middle frame 203 can enclose a receiving cavity. The receiving cavity is provided with a printed circuit board (PCB) 204, a battery 205, a speaker (not shown in the figure), a SIM card holder for carrying a SIM card, and a near field communication (NFC) coil (not shown in the figure). In the embodiment of the present application, the PCB 204 includes a main board 2041 and a sub-board 2042. The main board 2041 and the sub-board 2042 can be connected by a flexible printed circuit (FPC).

[0102] Continuing with Figures 2 and 3 , the wireless charging receiving device 20 also includes a wireless receiving device 22 and a load 21. Load 21 is a load resistor equivalent to the power consumption unit at the back end of the system. Load 21 can be a battery or other device that needs to be charged.

[0103] The wireless receiving device 22 includes a receiving coil L2 , a resonant capacitor C2 , and an AC / DC circuit 222 .

[0104] The receiving coil L2 is located in the receiving cavity, and for example, can be located between the battery 205 and the rear housing 201. The receiving coil L2 can be connected to the PCB 204 via an FPC (not shown in the figure).

[0105] The resonant capacitor C2 and the AC / DC circuit 222 are disposed on a PCB 204 (e.g., a mainboard 2041). The receiving coil L2 is connected to the resonant capacitor C2 and the AC / DC circuit 222 via an FPC and the PCB 204 (enabling signal transmission and interaction). In addition, the AC / DC circuit 222 is also connected to the load 21.

[0106] When the wireless charging transmitting device 10 needs to charge the wireless charging receiving device 20, the receiving coil L2 is close to or in contact with the transmitting coil L1. At this time, the receiving coil L2 in the wireless charging receiving device 20 generates alternating current through electromagnetic induction. The AC / DC circuit 222 converts the AC power generated by the receiving coil L2 into direct current and outputs it to the load 21 to power the load 21. Exemplarily, the AC / DC circuit 222 can be a rectifier bridge, and its circuit structure can be a full-bridge circuit or a half-bridge circuit. The AC / DC circuit 222 is also called a receiving (RX) chip.

[0107] In some embodiments, when the DC power output by the AC / DC circuit 222 is too large to be directly supplied to the load 21, the wireless receiving device 22 may further include a voltage conversion circuit 221. The voltage conversion circuit 221 is electrically connected to the AC / DC circuit 222 and the load 21, respectively, and is configured to reduce the larger voltage output by the AC / DC circuit 222 to the voltage required by the load 21. Exemplarily, the voltage conversion circuit 221 may be a step-down circuit (also known as a buck circuit).

[0108] In some embodiments, the voltage conversion circuit 221 can also be a switched capacitor (SC) circuit (not shown in the figure). The SC circuit can achieve, for example, a 2:1, 4:1 ratio step-down conversion. The specific structure of the SC circuit and the principle of achieving step-down conversion can be referred to the existing technology.

[0109] In some embodiments, the wireless charging receiving device 20 can also perform wired charging. When the wireless charging receiving device 20 can perform wired charging, the wireless charging receiving device 20 also includes a USB interface, which is electrically connected to the voltage conversion circuit 221. The charging signal received by the USB interface is transmitted to the voltage conversion circuit 221, so that the voltage conversion circuit 221 reduces the larger charging signal to the charging signal required by the load 21 to power the load 21. In some embodiments, an overvoltage protection (OVP) circuit is provided between the USB interface and the voltage conversion circuit 221, wherein the OVP circuit may include an OVP switch tube, which may be a MOSFET. When the OVP circuit detects that the voltage connected to the USB interface is too high (exceeds the threshold voltage), it can actively cut off the connection between the voltage conversion circuit 221 and the USB interface to protect the voltage conversion circuit 221.

[0110] The structure of wireless charging system 01 has been introduced above. As can be seen from the above, wireless charging technology uses the principle of electromagnetic coupling to achieve power transmission. Specifically, the alternating current carried by the transmitting coil on the wireless charging transmitting device generates a changing magnetic field, and the receiving coil on the wireless charging receiving device generates an induced current in the changing magnetic field, thereby charging the wireless charging receiving device. Therefore, a key component for implementing wireless charging technology is the wireless charging coil module, namely the transmitting coil L1 and / or receiving coil L2 mentioned above. However, the coil modules in the prior art are relatively thick. For example, the thickness of existing wireless charging coil modules is generally between 0.2mm and 0.3mm. This is not conducive to the configuration of functional components (such as functional components corresponding to biometric technology, functional components corresponding to high-quality imaging, functional components corresponding to artificial intelligence, etc.) within electronic devices with increasing functions (such as biometric technology, high-quality imaging, artificial intelligence, and other advanced functions).

[0111] To address the aforementioned issues, the present application provides a coil module that can be used in wireless charging receiving devices, i.e., the coil module can serve as a receiving coil in a wireless charging receiving device; it can also be used in wireless charging transmitting devices, i.e., the coil module can serve as a transmitting coil in a wireless charging transmitting device. The structure of the coil module provided in an embodiment of the present application is described in detail below.

[0112] It should be noted that the coil module provided in this application is not only applicable to wireless charging scenarios, but also to other scenarios that utilize the principle of electromagnetic induction.

[0113] Example 1

[0114] Referring to Figure 4 , which illustrates a film structure diagram of a coil module according to Example 1 of the present application, the coil module 30 includes a coil structure 31 and a magnetic conductive layer 32 , which are secured together by a double-sided adhesive layer (e.g., double-sided tape) 33 .

[0115] The provision of the magnetic conductive layer 32 can concentrate the magnetic field and increase the coil inductance of the coil module 30. Furthermore, as previously mentioned, the coil module 30 can be provided in the wireless charging receiving device 20, which may include structures such as the PCB 204, the battery 205, and the midframe 203. However, these structures are generally made of metal, and magnetic fields can generate eddy current losses in these structures. The provision of the magnetic conductive layer 32 can also partially shield the magnetic field, reducing the eddy current losses generated by the magnetic field in the PCB 204, the battery 205, the midframe 203, and the like.

[0116] Exemplarily, the magnetic conductive layer 32 includes two protective sublayers 321 and a magnetic conductive sublayer 322 located between the two protective sublayers 321, wherein the two protective sublayers 321 may include a first protective sublayer and a second protective sublayer, and the first protective sublayer is arranged adjacent to the coil structure 31. The protective sublayer 321 may be a nanocrystalline black film or polyimide (PI). The magnetic conductive sublayer 322 includes a soft magnetic material, which includes ferrite or nanocrystals. FIG4 illustrates the example of the soft magnetic material including nanocrystals. When the soft magnetic material includes nanocrystals, the magnetic conductive sublayer 322 includes multiple layers of nanocrystals 3221 and multiple layers of adhesive glue 3222 for bonding the nanocrystals 3221 together and located on both sides of the nanocrystals 3221. FIG4 illustrates the example of the magnetic conductive sublayer 322 including two layers of nanocrystals 3221 and three layers of adhesive glue 3222.

[0117] The thickness H21 of the protective sublayer 321 can be 5 μm, the thickness H22 of the nanocrystals 3221 can be 17 μm, and the thickness H23 of the adhesive 3222 can be 3 μm. In this case, the thickness H2 of the magnetic permeable layer 32 is 53 μm. Of course, the thickness of the protective sublayer 321, the thickness of the nanocrystals 3221, and / or the thickness of the adhesive 3222 can be adaptively varied to meet different requirements.

[0118] Continuing with FIG4 , the coil structure 31 may be an FPC coil and includes two protective films 311 and a functional layer 312 positioned between the two protective films 311. The protective films 311 include a PI layer 3111 and an adhesive 3112 that secures the PI layer 3111 to the functional layer 312. The functional layer 312 includes two wiring sublayers 3121 and an insulating sublayer 3122 positioned between the two adjacent wiring sublayers 3121. The two wiring sublayers 3121 include a first wiring sublayer and a second wiring sublayer.

[0119] The wiring sublayer 3121 can be a whole-surface metal layer, wherein the material of the metal layer includes copper, aluminum, nickel or alloy, etc., and then a coil is formed by etching the metal layer. The specific circuit design of the formed coil will be introduced in detail below and will not be repeated here.

[0120] To achieve electrical connection between the two wiring sub-layers 3121, a via is provided on the insulating sub-layer 3122 located between the two wiring sub-layers 3121. A connection structure 3124 is provided in the via to connect the two wiring sub-layers 3121. The present embodiment of the present application does not limit the manner in which the connection structure 3124 is formed. For example, referring again to FIG. 4 , an entire connection layer 3123 can be plated on the wiring sub-layer 3121. During the plating process, a portion of the material of the connection layer 3123 will be deposited into the via, forming the connection structure 3124. For another example, the connection structure 3124 can be formed directly in the via of the insulating sub-layer 3122.

[0121] For example, the thickness H11 of the PI layer 3111 can be 5 μm, the thickness H12 of the adhesive 3112 can be 5 μm, the thickness H13 of the insulating sublayer 3122 can be 12.5 μm, the thickness H14 of the wiring sublayer 3121 can be 12 μm, and the thickness H15 of the connecting layer 3123 can be 10 μm. In this case, the thickness H1 of the coil structure 31 is 76.5 μm. Alternatively, the thickness H11 of the PI layer 3111 can be 5 μm, the thickness H12 of the adhesive 3112 can be 5 μm, the thickness H13 of the insulating sublayer 3122 can be 12.5 μm, the thickness H14 of the wiring sublayer 3121 can be 18 μm, and the thickness H15 of the connecting layer 3123 can be 10 μm. In this case, the thickness H1 of the coil structure 31 is 88.5 μm.

[0122] In addition, the double-sided tape 33 between the coil structure 31 and the magnetic conductive layer 32 may be 7.5 μm thick.

[0123] Referring to Figures 5a-5d, Figure 5a is a three-dimensional view of a coil module provided in Example 1 of the present application, Figure 5b is a plan view of the coil module shown in Figure 5a, (1) in Figure 5b is a front view, (2) in Figure 5b is a back view, Figure 5c is an exploded view of the coil module shown in Figure 5a, and Figure 5d is an exploded view of the coil structure in the coil module shown in Figure 5a. As shown in Figures 4 and 5a-5d, the coil structure 31 includes a first end D1, a second end D2, and N groups of coil groups 31a connected in series. The first end D1 and the second end D2 are connected by the N groups of coil groups 31a connected in series, wherein one group of coil groups 31a is one circle (i.e., one turn) of the coil structure 31.

[0124] The N coil groups 31a can be toroidal coils, wherein the outer diameter d1 of the coil is less than or equal to 52mm and greater than or equal to 46mm; the inner diameter d2 of the coil is less than or equal to 28mm and less than or equal to 16mm. For example, the outer diameter d1 of the coil is 46mm, 47mm, 48mm, 49mm, 50mm, 51mm or 52mm; the inner diameter d2 of the coil is 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm or 28mm. It should be noted that the embodiments of the present application do not limit the specific form of the toroidal coil, and those skilled in the art can set it according to actual conditions. For example, the toroidal coil includes a circular toroidal coil, a rectangular toroidal coil, a hexagonal toroidal coil, an octagonal toroidal coil, etc. The embodiments of the present application are all described by taking the toroidal coil as an example.

[0125] The first end D1 and multiple coil assemblies 31a are formed by etching the first wiring sublayer and the connection layer 3123 located thereon. The second end D2 and multiple coil assemblies 31a are formed by etching the second wiring sublayer and the connection layer 3123 located thereon. The outermost coil assemblies 31a of the N coil assemblies 31a are connected to the first end D1, while the innermost coil assemblies 31a of the N coil assemblies 31a are connected to the second end D2 via the connection structure 3124 within the via hole in the insulating sublayer 3122. This connects the first end D1 to the second end D2 through the multiple coil assemblies 31a connected in series.

[0126] Continuing to refer to Figures 4 and 5a-5d, a hollow portion 32a is defined on the magnetic conductive layer 32, and the second end D2 of the coil structure 31 is embedded in the hollow portion 32a. In this way, the second end D2 can be prevented from occupying the thickness direction of the coil module 30, thereby reducing the thickness of the coil module 30. For example, the thickness can be reduced to H11+H12+H14+H15=5+5+10+12=32μm; or the thickness can be reduced to H11+H12+H14+H15=5+5+10+18=38μm.

[0127] In order to further reduce the thickness of the coil module 30, referring to Figure 4, a part of the protective sublayer (i.e., the first protective sublayer) 321 in the magnetic conductive layer 32 that is in contact with the coil structure 31 is hollowed out. The hollowing can expose the adhesive 3222 between the protective sublayer 321 and the nanocrystal 3221. The double-sided tape 33 that bonds the coil structure 31 and the magnetic conductive layer 32 is located in the hollow portion 3211 and is in contact with the adhesive 3222 between the protective sublayer 321 and the nanocrystal 3221.

[0128] It is understood that to ensure the bonding strength between the coil structure 31 and the magnetic conductive layer 32, the thickness of the double-sided tape 33 still needs to be maintained at 7.5 μm. Therefore, the thickness of the protective sublayer 321 in the magnetic conductive layer 32 that contacts the coil structure 31 and the film layer where the double-sided tape 33 is located is 7.5 μm. This allows the thickness of the coil module 30 to be reduced by 5 μm (the thickness of one protective sublayer 321).

[0129] Through the above configuration, the thickness of the coil module 30 can be made 100 μm or 106 μm, that is, the thickness of the wireless charging coil module is made extremely thin, so that the coil module occupies less space inside the electronic device, which is conducive to the configuration of other structures.

[0130] In some embodiments, referring again to FIG. 4 , the adhesive 3222 disposed adjacent to the second protective sublayer is the first adhesive. The first protective sublayer, the adhesives 3222 other than the first adhesive, and the film layer containing the nanocrystals 3221 are each provided with a first opening 32a1. The film layer containing the first adhesive and the second protective sublayer is provided with a second opening 32a2. The first and second openings form a hollow portion 32a. The first opening 32a1 is larger than the second opening 32a2, meaning that the projection of the second opening 32a2 on the second protective sublayer is within the projection of the first opening 32a1 on the second protective sublayer.

[0131] In this way, the nanocrystalline powder can be prevented from falling out, making the structure of the coil module more reliable.

[0132] The above describes the film structure of the coil module 30. From the above content, it can be seen that the thickness of the coil module 30 of the present application can be only 0.1Xmm. It can be understood that when the thickness of the coil module is thin, the impedance of the coil module is generally large, and a large impedance is not conducive to high-power charging of the wireless charging receiving device. In order to achieve the effect of high-power charging and thinness of the wireless charging receiving device, continuing with Figures 5a-5d, the number N of coil groups 31a is less than or equal to 8, and greater than or equal to 7, that is, the number of turns of the coil structure 31 is 7 turns to 8 turns. For example, the number of turns of the coil structure 31 can be 7 turns (as shown in Figure 5c) or 8 turns (as shown in Figure 6), etc. Of course, the number of turns of the coil structure 31 can also be 7.5 turns, and 0.5 turns is half a turn of the wire. For example, the 7.5 turns may be formed by winding half a turn on the outermost coil group 31 a among the seven coil groups 31 a , or may be formed by winding half a turn on the innermost coil group 31 a among the seven coil groups 31 a .

[0133] When the number of turns of the coil structure 31 is 7 to 8 turns, the coil structure 31 can achieve both high-power and high-freedom wireless charging effects. The charging power will not be affected due to too many turns and high impedance, nor will the degree of freedom of the coil structure 31 be low due to too few turns. That is, when the coil module 30 is applied to the wireless charging receiving device 20, when the number of turns of the transmitting coil in the wireless charging transmitting device 10 is constant (such as 12 turns), the offset distance between the center of the receiving coil and the center of the transmitting coil is small, so strict alignment is required, which makes the degree of freedom of the coil structure 31 low.

[0134] In some embodiments, each coil assembly 31a includes M strands of wire 311a, where M can be less than or equal to 4 and greater than or equal to 2. For example, M is 2, 3, or 4. FIG. 5c and FIG. 6 illustrate the example of M being 3. That is, the coil structure 31 is continuously wound from the first end D1 (forming N coil assemblies 31a connected in series) to the second end D2, distributed across two wiring sub-layers 3121. Current is input from the first end D1, passes through the N coil assemblies 31a, and is output from the second end D2.

[0135] By setting M to be less than or equal to 4 and greater than or equal to 2, there will be no waste of routing space due to a large number of wires 311a, resulting in a large gap between two adjacent wires 311a, nor will there be a small number of wires 311a, resulting in fewer channels for current flow due to the skin effect, thus affecting current transmission.

[0136] The number of strands in each coil group 31a can be determined based on the actual number of turns of the coil structure 31 and the thickness of the wiring sublayer 3121, so that the coil structure 31 can achieve both high-power and high-freedom wireless charging effects.

[0137] In one possible implementation, see Figure 7, which is an exploded view of another coil module provided in Example 1 of the present application. As shown in Figure 7, there are seven coil groups 31a, the thickness of the first wiring sublayer is greater than or equal to 25μm and less than or equal to 40μm, and each coil group 31a includes M strands of wire 311a, where M is greater than or equal to 3, for example, M is 4.

[0138] With this arrangement, even if the coil assembly 31 a is thick, it is possible to avoid large eddy current losses being generated in the thick coil assembly 31 a.

[0139] It should be noted that, in the embodiment of the present application, when a connection layer 3123 is provided on the first wiring sub-layer, the thickness of the first wiring sub-layer also includes the thickness of the connection layer 3123 .

[0140] In another possible implementation, referring to FIG5c , the number of coil groups 31a is 7, the thickness of the first wiring sublayer is less than or equal to 25 μm, and each coil group 31a includes M strands of wire 311a , where M is less than or equal to 4, such as 3.

[0141] Because the M strands of conductive wire 311a are formed by cutting and routing, when M is less than or equal to 4, it can avoid wasting a lot of routing space and can also ensure more flow channels, thereby having a better flow effect.

[0142] In another possible implementation, referring to Figure 6 , the number of coil groups is 8, the thickness of the first wiring sublayer is greater than or equal to 25 μm and less than or equal to 40 μm, and each coil group 31a includes M strands of wire 311a, where M is greater than or equal to 2, such as 3.

[0143] This arrangement can avoid large eddy current losses in the thicker coil group 31a even if the coil group 31a is thicker, and will not increase the impedance due to the increase in the number of coil groups.

[0144] In another possible implementation, see Figure 8, which is an exploded view of another coil module provided in Example 1 of the present application. As shown in Figure 8, the number of coil groups 31a is 8, the thickness of the first wiring sublayer is less than or equal to 25μm, and each coil group 31a includes M strands of wire 311a, where M is less than or equal to 3, for example, M is 3.

[0145] Because the M strands of wire 311a are formed by cutting and routing, when M is less than or equal to 3, it can avoid wasting much routing space and can also achieve a better current flow effect. Furthermore, the impedance will not be increased due to the increase in the number of coil groups.

[0146] In some embodiments, referring to FIG5c , N coil groups 31a include L internal coil groups 31a-I and (NL) external coil groups 31a-O arranged around the L internal coil groups; each coil group 31a includes multiple strands of wire 311a; the number of strands of wire located in the external coil group 31a-O is greater than the number of strands of wire located in the internal coil group 31a-I.

[0147] Since the magnetic field strength inside the coil structure 31 is stronger and the magnetic field strength outside is weaker, the number of wire strands in the outer coil group 31a-O is set to be greater than the number of wire strands in the inner coil group 31a-I. This can ensure that the outer coil group 31a-O has more current channels and improve the uniformity of current distribution.

[0148] The specific value of L is not limited in the embodiments of this application, and those skilled in the art can set it according to actual circumstances. For example, if N is 7 and L is 3, there are 7 coil groups 31a, and the coil groups from the innermost circle to the outermost circle are the first coil group, the second coil group, the third coil group, the fourth coil group, the fifth coil group, the sixth coil group, and the seventh coil group. The 7 coil groups 31a include 3 internal coil groups 31a-I and 4 external coil groups 31a-O arranged around the 3 internal coil groups. That is, the first coil group, the second coil group, and the third coil group are the internal coil groups 31a-I, and the fourth coil group, the fifth coil group, the sixth coil group, and the seventh coil group are the external coil groups 31a-O. The fourth coil group, the fifth coil group, the sixth coil group, and the seventh coil group have the same number of wire strands. The first coil group, the second coil group, and the third coil group have the same number of wire strands. The fourth coil group, the fifth coil group, the sixth coil group, and the seventh coil group have more wire strands than the first coil group, the second coil group, and the third coil group.

[0149] In some embodiments, referring to FIG. 6 , along a direction away from the center of the coil structure, such as the direction indicated by arrow XX in FIG. 6 , the width W0 of the plurality of coil groups 31 a gradually increases.

[0150] The widths of the multiple coil groups 31a may be gradually increased in a direction away from the center of the coil structure. For example, the number of coil groups 31a is eight, and the coil groups 31a, from the innermost circle to the outermost circle, are divided into a first coil group, a second coil group, a third coil group, a fourth coil group, a fifth coil group, a sixth coil group, a seventh coil group, and an eighth coil group. The widths of the first coil group, the second coil group, the third coil group, the fourth coil group, the fifth coil group, the sixth coil group, the seventh coil group, and the eighth coil group increase in sequence. That is, the width of the eighth coil group is greater than the width of the seventh coil group, the width of the seventh coil group is greater than the width of the sixth coil group, the width of the sixth coil group is greater than the width of the fifth coil group, the width of the fifth coil group is greater than the width of the fourth coil group, the width of the fourth coil group is greater than the width of the third coil group, the width of the third coil group is greater than the width of the second coil group, and the width of the second coil group is greater than the width of the first coil group.

[0151] The widths of the multiple coil groups 31a may also gradually increase: as they move away from the center of the coil structure, some adjacent coil groups 31a have the same width, while the widths of coil groups 31a with different widths gradually increase. For example, there are eight coil groups 31a, and the coil groups 31a, from the innermost to the outermost, are divided into a first coil group, a second coil group, a third coil group, a fourth coil group, a fifth coil group, a sixth coil group, a seventh coil group, and an eighth coil group. The first and second coil groups have the same widths, the third, fourth, and fifth coil groups have the same widths, and the sixth, seventh, and eighth coil groups have the same widths. The widths of the first, third, and sixth coil groups increase in that order.

[0152] Since the magnetic field strength inside the coil structure 31 is relatively strong and the magnetic field strength outside is relatively weak, the width of the innermost coil group 31a, the width of the middle coil group 31a, and the width of the outermost coil group 31a are set to increase in sequence. This can gradually enhance the current carrying capacity of the innermost coil group 31a, the middle coil group 31a, and the outermost coil group 31a, thereby improving the uniformity of current distribution.

[0153] It should be noted here that, when the width W0 of the multiple coil groups 31a gradually increases in the direction away from the center of the coil structure, the number of strands of the wire 311a of each coil group 31a can be the same, such as 3 strands or 4 strands; of course, the number of strands of the wire 311a of each coil group 31a can also be different.

[0154] To facilitate understanding of the above content, the specific structure of the coil module 30 provided in the embodiment of the present application will be introduced below with reference to specific examples.

[0155] Example 1, continuing to refer to Figures 4 and 7, the coil inner diameter d1 is 20 mm, the coil outer diameter d2 is 48 mm, N is 7, and M is 4. That is, within the limited area defined by the coil outer diameter d2 of 48 mm and the coil inner diameter d1 of 20 mm, the coil structure 31 adopts a 7-turn 4-strand parallel winding scheme; the magnetic conductive sublayer 322 includes two layers of nanocrystals 3221 (the thickness of each layer of nanocrystals 3221 is 17 μm), and the material properties of the nanocrystals meet the following requirements: the saturation magnetic flux density of the nanocrystals is 1.4 T, and the relative magnetic permeability of the nanocrystals is 3000 times that of air (i.e., μ'3000).

[0156] The electrical parameters in this example are shown in Table 1. In Table 1, L is the inductance of the coil module, Q is the quality factor of the coil module, ARC is the AC impedance of the coil module, and DRC is the DC impedance of the coil module.

[0157] Table 1

[0158] It can be seen from Table 1 that under different electromagnetic wave frequencies, the inductance L of the coil module will also change. And as the frequency increases, the AC impedance ARC increases, but the AC impedance ARC and the DC impedance DRC are both small. And the coil module of this example has a good quality factor Q. In addition, the self-resonant frequency of the coil module of this example is 8.9253Mhz, which is far from the operating frequency of the coil module (100KHZ, 130KHZ or 145KHZ, etc.) and will not affect wireless charging. In other words, the coil module provided in this example has a small impedance and a more suitable inductance at an extremely small thickness (e.g., a thickness of 0.110mm), which is conducive to high-power wireless charging.

[0159] Furthermore, the seven coil assemblies 31a are divided, from the inside out, into the first, second, third, fourth, fifth, sixth, and seventh coil assemblies. The third, fourth, and fifth coil assemblies have the same width, while the sixth and seventh coil assemblies have the same width. The widths of the first, second, third, and sixth coil assemblies gradually increase. The wiring design of the seven coil assemblies 31a is shown in Table 2. The four strands of wire 311a in each coil assembly 31a have a spacing of 0.06 mm. It is understood that spacing is related to the manufacturing process, and a smaller spacing is preferred.

[0160] Table 2

[0161] The coil module in this example was subjected to a current density distribution test, and the test results are shown in FIG9 , wherein (1) in FIG9 is the current density distribution of the coil module 30 , and the colors corresponding to each position in the coil module 30 represent the current values. (2) in FIG9 is the correspondence between the colors and the current values, that is, the colors of each position in (1) in FIG9 are matched with the colors and current values ​​provided by (2) in FIG9 to determine the current values ​​of each position in (1) in FIG9 .

[0162] As shown in Figure 9, the current density distribution test results show that the color corresponding to each position in the coil module 30 is relatively uniform, with minimal color variation, indicating good color consistency across all positions. This indicates that using the coil module in this example ensures current flow at all positions, with a relatively uniform current density distribution, which is beneficial for high-power wireless charging.

[0163] In summary, the coil module provided in this example can enable wireless charging receiving devices to achieve both high-power charging and lightweight effects.

[0164] To better illustrate this effect, a simulation test was conducted on the coil module provided in the embodiment of the present application. The simulation test results are shown in Table 3, where the offset in Table 3 is the offset distance between the center of the transmitting coil and the center of the receiving coil, and positive and negative values ​​can respectively represent that the center of the receiving coil is offset to the left and right relative to the center of the transmitting coil; the target power is the charging efficiency under different loads; the input voltage and input current are the voltage and current provided by the wireless charging transmitting device; the output voltage and output current are the voltage and current generated by the wireless charging receiving device based on the voltage and current provided by the wireless charging transmitting device; the input power is the product of the input voltage and the input current; the output power is the product of the output voltage and the output current; and the efficiency is the ratio of the output power to the input power.

[0165] Table 3 Charging efficiency at different offsets

[0166] As can be seen from Table 3, the ultra-thin coil module provided in the embodiment of the present application can also support 30W high-power wireless charging.

[0167] Example 2, continuing to refer to Figures 4 and 5c, the coil inner diameter d1 is 20 mm, the coil outer diameter d2 is 48 mm, N is 7, and M is 3. That is, within the limited area defined by the coil outer diameter d2 of 48 mm and the coil inner diameter d1 of 20 mm, the coil structure 31 adopts a 7-turn 3-strand parallel winding scheme; the magnetic conductive sublayer 322 includes two layers of nanocrystals 3221 (the thickness of each layer of nanocrystals 3221 is 17 μm), and the material properties of the nanocrystals meet the following requirements: the saturation magnetic flux density of the nanocrystals is 1.4 T, and the relative magnetic permeability of the nanocrystals is 3000 times that of air (i.e., μ'3000).

[0168] The electrical parameters in this example are shown in Table 4. In Table 4, L is the inductance of the coil module, Q is the quality factor of the coil module, ARC is the AC impedance of the coil module, and DRC is the DC impedance of the coil module.

[0169] Table 4

[0170] It can be seen from Table 4 that the inductance L of the coil module will also change under different electromagnetic wave frequencies. And as the frequency increases, the AC impedance ARC increases, but the AC impedance ARC and the DC impedance DRC are both small. And the coil module of this example has a good quality factor Q. In addition, the self-resonant frequency of the coil module of this example is 7.8173Mhz, which is far from the operating frequency of the coil module (100KHZ, 130KHZ or 145KHZ, etc.) and will not affect wireless charging. In other words, the coil module provided in this example has a small impedance and a more suitable inductance at an extremely small thickness (e.g., a thickness of 0.102mm).

[0171] From the inside out, the seven coil assemblies 31a are divided into the first, second, third, fourth, fifth, sixth, and seventh coil assemblies. The first and second coil assemblies have the same width, while the fifth and sixth coil assemblies have the same width. The widths of the first, third, fourth, fifth, and seventh coil assemblies gradually increase. The wiring design of the seven coil assemblies 31a is shown in Table 5. The spacing between the three wires 311a in each coil assembly 31a is 0.06 mm. It is understood that the spacing depends on the process level, and the smaller the spacing, the better.

[0172] Table 5

[0173] The coil module in this example was subjected to a current density distribution test, and the test results are shown in FIG10 , wherein (1) in FIG10 is the current density distribution of the coil module 30, and the color corresponding to each position in the coil module 30 represents the current value. (2) in FIG10 is the correspondence between the color and the current value, that is, the color of each position in (1) in FIG10 is matched with the color and current value provided by (2) in FIG10 to determine the current value of each position in (1) in FIG10 .

[0174] As shown in Figure 10, the current density distribution test results show that the color corresponding to each position in the coil module 30 is relatively uniform, with minimal color variation, indicating good color consistency across all positions. This indicates that using the coil module in this example ensures current flow at all positions, with a relatively uniform current density distribution, which is beneficial for high-power wireless charging.

[0175] In summary, the coil module provided in this example can enable wireless charging receiving devices to have both high-power charging and lightweight effects.

[0176] To better illustrate this effect, a simulation test was conducted on the coil module provided in the embodiment of the present application. The simulation test results are shown in Table 6, where the offset in Table 6 is the offset distance between the center of the transmitting coil and the center of the receiving coil, and positive and negative values ​​respectively represent that the center of the receiving coil is offset to the left and right relative to the center of the transmitting coil; the target power is the charging efficiency under different loads; the input voltage and input current are the voltage and current provided by the wireless charging transmitting device; the output voltage and output current are the voltage and current generated by the wireless charging receiving device based on the voltage and current provided by the wireless charging transmitting device; the input power is the product of the input voltage and the input current; the output power is the product of the output voltage and the output current; and the efficiency is the ratio of the output power to the input power.

[0177] Table 6 Charging efficiency at different offsets

[0178] As can be seen from Table 6, the ultra-thin coil module provided in the embodiment of the present application can also support 30W high-power wireless charging.

[0179] Example 3, continuing to refer to Figures 4 and 6, the coil inner diameter d1 is 20 mm, the coil outer diameter d2 is 48 mm, N is 8, and M is 3. That is, within the limited area defined by the coil outer diameter d2 of 48 mm and the coil inner diameter d1 of 20 mm, the coil structure 31 adopts an 8-turn 3-strand parallel winding scheme; the magnetic conductive sublayer 322 includes two layers of nanocrystals 3221 (the thickness of each layer of nanocrystals 3221 is 17 μm), and the material properties of the nanocrystals meet the following requirements: the saturation magnetic flux density of the nanocrystals is 1.4 T, and the relative magnetic permeability of the nanocrystals is 3000 times that of air (i.e., μ'3000).

[0180] The electrical parameters in this example are shown in Table 7. In Table 7, L is the inductance of the coil module, Q is the quality factor of the coil module, ARC is the AC impedance of the coil module, and DRC is the DC impedance of the coil module.

[0181] Table 7

[0182] It can be seen from Table 7 that the inductance L of the coil module will also change under different electromagnetic wave frequencies. And as the frequency increases, the AC impedance ARC increases, but the AC impedance ARC and the DC impedance DRC are both small. And the coil module of this example has a good quality factor Q. In addition, the self-resonant frequency of the coil module of this example is 7.8172Mhz, which is far from the operating frequency of the coil module (100KHZ, 130KHZ or 145KHZ, etc.) and will not affect wireless charging. In other words, the coil module provided in this example has a small impedance and a more suitable inductance at an extremely small thickness (e.g., a thickness of 0.109mm), which is conducive to high-power wireless charging.

[0183] From the inside out, the eight coil assemblies 31a are divided into the first, second, third, fourth, fifth, sixth, seventh, and eighth coil assemblies. The first, second, third, and fourth coil assemblies have the same width, while the fifth, sixth, and seventh coil assemblies have the same width. The widths of the first, fifth, and eighth coil assemblies gradually increase. The wiring design of the eight coil assemblies 31a is shown in Table 8. The spacing between the three wires 311a in each coil assembly 31a is 0.06 mm. It is understood that the spacing depends on the process level, and the smaller the spacing, the better.

[0184] Table 8

[0185] The coil module in this example was subjected to a current density distribution test, and the test results are shown in FIG11 , wherein (1) in FIG11 is the current density distribution of the coil module 30, and the colors corresponding to each position in the coil module 30 represent the current values. (2) in FIG11 is the correspondence between the colors and the current values, that is, the colors of each position in (1) in FIG11 are matched with the colors and current values ​​provided by (2) in FIG11 to determine the current values ​​of each position in (1) in FIG11 .

[0186] As shown in Figure 11, the current density distribution test results show that the color corresponding to each position in the coil module 30 is relatively uniform, with minimal color variation, indicating good color consistency across all positions. This indicates that the coil module in this example provides current flow at all positions, with a relatively uniform current density distribution, which is beneficial for high-power wireless charging.

[0187] In summary, the coil module provided in this example can enable wireless charging receiving devices to achieve both high-power charging and lightweight effects.

[0188] To better illustrate this effect, a simulation test was conducted on the coil module provided in the embodiment of the present application. The simulation test results are shown in Table 9, where the offset in Table 9 is the offset distance between the center of the transmitting coil and the center of the receiving coil, and positive and negative values ​​respectively represent that the center of the receiving coil is offset to the left and right relative to the center of the transmitting coil; the target power is the charging efficiency under different loads; the input voltage and input current are the voltage and current provided by the wireless charging transmitting device; the output voltage and output current are the voltage and current generated by the wireless charging receiving device based on the voltage and current provided by the wireless charging transmitting device; the input power is the product of the input voltage and the input current; the output power is the product of the output voltage and the output current; and the efficiency is the ratio of the output power to the input power.

[0189] Table 9 Charging efficiency at different offsets

[0190] As can be seen from Table 9, the ultra-thin coil module provided in the embodiment of the present application can also support 30W high-power wireless charging.

[0191] Example 4, continuing to refer to Figures 4 and 8, the coil inner diameter d1 is 20mm, the coil outer diameter d2 is 48mm, N is 8, and M is 3. That is, in the limited area defined by the coil outer diameter d2 being 48mm and the coil inner diameter d1 being 20mm, the coil structure 31 adopts an 8-turn 3-strand parallel winding scheme; the magnetic permeability sublayer 3222 includes two layers of nanocrystals 3221 (the thickness of each layer of nanocrystals 3221 is 17μm), and the material properties of the nanocrystals meet the following requirements: the saturation magnetic flux density of the nanocrystals is 1.4T, and the relative magnetic permeability of the nanocrystals is 3000 times that of air (i.e., μ'3000). It should be noted that the thickness of the wiring sublayers of Examples 1 and 3 is the same, for example, both are 18μm, and the thickness of the wiring sublayers of Examples 2 and 4 is the same, for example, both are 12μm. The thickness of the other film layers of Examples 1, 2, 3, and 4 is the same.

[0192] The electrical parameters in this example are shown in Table 10. In Table 10, L is the inductance of the coil module, Q is the quality factor of the coil module, ARC is the AC impedance of the coil module, and DRC is the DC impedance of the coil module.

[0193] Table 10

[0194] It can be seen from Table 10 that under different electromagnetic wave frequencies, the inductance L of the coil module will also change. And as the frequency increases, the AC impedance ARC increases, but the AC impedance ARC and the DC impedance DRC are both small. And the coil module of this example has a good quality factor Q. In addition, the self-resonant frequency of the coil module of this example is 7.8172Mhz, which is far from the operating frequency of the coil module (100KHZ, 130KHZ or 145KHZ, etc.) and will not affect wireless charging. In other words, the coil module provided in this example has a small impedance and a more suitable inductance at an extremely small thickness (e.g., a thickness of 0.109mm), which is conducive to high-power wireless charging.

[0195] From the inside out, the eight coil assemblies 31a are divided into the first, second, third, fourth, fifth, sixth, seventh, and eighth coil assemblies. The first, second, third, and fourth coil assemblies have the same width, while the fifth, sixth, and seventh coil assemblies have the same width. The widths of the first, fifth, and eighth coil assemblies gradually increase. The circuit design of the eight coil assemblies 31a is shown in Table 11. The spacing between the three wires 311a in each coil assembly 31a is 0.06 mm. It is understood that the spacing depends on the process level, and the smaller the spacing, the better.

[0196] Table 11

[0197] In summary, the coil module provided in this example can enable wireless charging receiving devices to have both high-power charging and lightweight effects.

[0198] In order to better illustrate this effect, a simulation test was conducted on the coil module provided in the embodiment of the present application, and the simulation test results are shown in Table 12, where the offset in Table 12 is the offset distance between the center of the transmitting coil and the center of the receiving coil, and positive and negative values ​​can respectively represent that the center of the receiving coil is offset to the left and right relative to the center of the transmitting coil; the target power is the charging efficiency under different loads; the input voltage and input current are the voltage and current provided by the wireless charging transmitting device; the output voltage and output current are the voltage and current generated by the wireless charging receiving device based on the voltage and current provided by the wireless charging transmitting device; the input power is the product of the input voltage and the input current; the output power is the product of the output voltage and the output current; and the efficiency is the ratio of the output power to the input power.

[0199] Table 12 Charging efficiency at different offsets

[0200] As can be seen from Table 12, the ultra-thin coil module provided in the embodiment of the present application can also support 30W high-power wireless charging.

[0201] From the above four examples, it can be seen that the ultra-thin coil module provided in this application can also support 30W high-power wireless charging.

[0202] Example 2

[0203] Referring to Figures 12, 13, and 14, Figure 12 is a film layer diagram of a coil module provided in Example 2 of the present application, Figure 13 is a plan view of a coil module provided in Example 2 of the present application, and Figure 14 is an exploded view of the coil module shown in Figure 13. As shown in Figures 12, 13, and 14, unlike Example 1, the magnetic conductive layer 32 in Example 2 is located on one side of the coil structure 31, and the magnetic conductive layer 32 does not have a hollow portion 32a. Accordingly, the second wiring sublayer, in which the second end D2 of the coil structure 31 is located, is located between the first wiring sublayer and the magnetic conductive layer 32. In this embodiment, the coil structure 31 further includes at least one flexible circuit board unit 31b. The flexible circuit board unit 31b and the second end D2 of the coil structure 31 are both located in the second wiring sublayer, wherein the flexible circuit board unit 31b is located in a predetermined area of ​​the second wiring sublayer, which is the area of ​​the second wiring sublayer where the second end D2 is not located.

[0204] It should be noted that, unless otherwise specified, the specific structure of the coil module 30 in the embodiment of the present application (such as the thickness of each film layer, the number of groups, the number of strands and the width design of the coil group 31a, etc.) is the same as that in Example 1. Please refer to Example 1 for details and will not be repeated here.

[0205] That is to say, when the coil module is provided in an electronic device, the flexible circuit board in the electronic device can be provided in the second wiring sublayer, that is, the coil module includes both the wireless charging coil and the flexible circuit board in the electronic device. In this way, the internal space of the electronic device is avoided from being occupied by other flexible circuit boards, which is conducive to the setting of other structures and can also reduce the process steps.

[0206] As can be seen from the foregoing, the main board 2041 and the secondary board 2042 can be connected via an FPC. Therefore, in one example, the FPC unit connecting the main board 2041 and the secondary board 2042 can be located in a predetermined area of ​​the second wiring sublayer. This eliminates the need to separately install an FPC connecting the main board 2041 and the secondary board 2042 within the housing of the electronic device, thus preventing the FPC from occupying space within the electronic device and facilitating the installation of other components. Furthermore, the FPC unit can be formed simultaneously with the formation of the second end D2, thus reducing the number of process steps.

[0207] Since the NFC coil can be wound with FPC wiring, in another example, the NFC coil can be placed in a preset area of ​​the second wiring sublayer. This eliminates the need to separately place the NFC coil in the housing cavity of the electronic device, thus preventing the NFC coil from occupying the internal space of the electronic device and facilitating the placement of other structures. Furthermore, the NFC coil can be formed simultaneously with the formation of the second end D2, thus reducing the number of process steps.

[0208] In addition, functional components such as the wireless charging coil (such as the receiving coil L2), speakers, and SIM cards are all connected to the main board 2041 or the sub-board 2042 through FPC. Therefore, in another example, the FPC connecting the functional components and the main board 2041 or the sub-board 2042 can be set in a preset area of ​​the second wiring sub-layer. In this way, there is no need to separately set the FPC connecting the functional components and the main board 2041 or the sub-board 2042 in the accommodating cavity of the electronic device, thereby avoiding the FPC occupying the internal space of the electronic device, which is conducive to the arrangement of other structures, and the FPC is formed at the same time as the second end D2 is formed, thereby reducing the process steps.

[0209] It should be noted that the above examples are only used as an example to illustrate that the lines connecting the FPC, NFC coil or connecting functional devices (such as wireless charging coil, speaker, SIM card, etc.) of the main board 2041 and the sub-board 2042 and the FPC of the main board 2041 or the sub-board 2042 are arranged in the second wiring sub-layer, but it does not constitute a limitation of the present application. Under the condition that the working requirements of each functional device are met, other FPCs in the electronic device can be arranged in the preset area of ​​the second wiring sub-layer.

[0210] In some embodiments, the predetermined area includes a first sub-area YY, which is formed by the projection of the outermost coil assembly on the second wiring sub-layer extending in all directions by a first predetermined length W1 (i.e., the annular area enclosed by the inner and outer annular dashed lines in FIG. 13 ). When the line width W2 of the flexible circuit board unit 31b within the first sub-area YY is greater than the second predetermined length, the wiring of the flexible circuit board unit 31b within the first sub-area YY is cut into multiple lines. In other words, the wider wiring of the flexible circuit board unit 31b within the first sub-area YY is cut into multiple thin lines, thereby preventing excessive eddy current losses from occurring in the wider wiring.

[0211] For example, the first preset length can be 5 mm, and the second preset length can be 8 mm. That is, at least within 5 mm of the maximum extension of the coil, avoid having traces with a width greater than 8 mm. Wider traces within this range can be cut into strands, and the thinner the trace width, the better.

[0212] It can be seen from the above two embodiments that multiple coil groups occupying a larger area are arranged on the first wire sub-layer, while the second wiring sub-layer only includes the second end occupying a smaller area. In this way, when the coil module is set in the electronic device, other wiring of the electronic device can be set on the second wiring sub-layer to avoid other wiring occupying the internal space of the electronic device, which is conducive to the arrangement of other structures. Alternatively, since the second wiring sub-layer only has the second end occupying a smaller area, the second end occupying a smaller area can be embedded in other structures, so that the coil module occupies less space inside the electronic device, which is conducive to the arrangement of other structures.

[0213] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A coil module, characterized in that, include: Coil structure; The coil structure comprises a functional layer, and along a thickness direction of the coil structure, the functional layer comprises a first wiring sub-layer, a second wiring sub-layer, and an insulating sub-layer located between the first wiring sub-layer and the second wiring sub-layer; The coil structure comprises a first end, a second end and a plurality of coil groups connected in series in sequence, the first end and the plurality of coil groups are arranged in the first wiring sub-layer, and the outermost coil group is connected to the first end; The second end is arranged on the second wiring sublayer; a via is opened on the insulating sublayer, and a connecting structure is arranged in the via; the innermost coil group is connected to the second end through the connecting structure in the insulating sublayer, so that the first end is electrically connected to the second end through multiple coil groups connected in series in sequence.

2. The coil module according to claim 1, wherein, The coil module further includes: a magnetic conductive layer; the magnetic conductive layer includes a hollow portion, and the second end is arranged in the hollow portion.

3. The coil module according to claim 2, wherein Along the thickness direction of the coil structure, the magnetic conductive layer includes a first protective sublayer, a second protective sublayer and a magnetic conductive sublayer located between the first protective sublayer and the second protective sublayer, and the magnetic conductive sublayer includes multiple layers of adhesive and nanocrystals located between two adjacent layers of the adhesive; The first protective sublayer is disposed adjacent to the coil structure, and the adhesive disposed adjacent to the second protective sublayer is a first adhesive; The first protective sublayer, the other adhesives except the first adhesive, and the film layer where the nanocrystals are located are provided with a first opening, the film layer where the first adhesive and the second protective sublayer are located are provided with a second opening, and the first opening and the second opening form the hollow portion; The projection of the second opening on the reference plane is located within the projection of the first opening on the reference plane, and the reference plane is perpendicular to the thickness direction of the coil structure.

4. The coil module according to claim 3, wherein, The thickness of the coil module is less than 0.2 mm.

5. The coil module according to claim 1, wherein The coil structure further includes a flexible circuit board unit; the flexible circuit board unit is located in a preset area of the second wiring sub-layer, and the preset area is an area of the second wiring sub-layer where the second end is not provided.

6. The coil module according to claim 5, wherein, The preset area includes a first sub-area, and the first sub-area is an area formed by extending the projection of the outermost coil group on the second wiring sub-layer by a first preset length in all directions; When the line width of the flexible circuit board unit in the first sub-area is greater than the second preset length, the routing line of the flexible circuit board unit in the first sub-area is cut into multiple lines.

7. The coil module according to claim 5, wherein The coil module further includes: a magnetic conductive layer; along the thickness direction of the coil structure, the magnetic conductive layer is located on a side of the second wiring sub-layer away from the first wiring sub-layer.

8. The coil module according to any one of claims 1-7, characterized in that The number of the coil groups is N, where N is less than or equal to 8 and greater than or equal to 7.

9. The coil module according to claim 8, wherein The number of the coil groups is 7, the thickness of the first wiring sublayer is greater than or equal to 25 μm and less than or equal to 40 μm, and each coil group includes M strands of wire, where M is greater than or equal to 3.

10. The coil module according to claim 9, wherein, M is 4.

11. The coil module according to claim 8, characterized in that, The number of the coil groups is 7, the thickness of the first wiring sub-layer is less than or equal to 25 μm, and each coil group includes M strands of wire, where M is less than or equal to 4.

12. The coil module according to claim 11, wherein M is 3.

13. The coil module according to claim 8, wherein The number of the coil groups is 8, the thickness of the first wiring sub-layer is greater than or equal to 25 μm and less than or equal to 40 μm, and each coil group includes M strands of wires, where M is greater than or equal to 2.

14. The coil module according to claim 13, characterized in that, M is 3.

15. The coil module according to claim 8, wherein The number of the coil groups is 8, the thickness of the first wiring sub-layer is less than or equal to 25 μm, and each coil group includes M strands of wires, where M is less than or equal to 3.

16. The coil module according to claim 15, wherein, M is 3.

17. The coil module according to any one of claims 1-16, characterized in that, In the direction away from the center of the coil structure, the widths of multiple coil groups gradually increase.

18. The coil module according to any one of claims 1-16, characterized in that, The number of the coil groups is N, and the N coil groups include L internal coil groups and (N - L) external coil groups arranged around the L internal coil groups; Each coil group includes multiple strands of wires; The number of wire strands in the external coil groups is greater than that in the internal coil groups.

19. The coil module according to any one of claims 1-18, characterized in that The coil structure is an FPC coil.

20. An electronic device, characterized in that, It includes the coil module according to any one of claims 1 - 19.

21. The electronic device according to claim 20, wherein The coil structure further includes at least one flexible circuit board unit; the flexible circuit board unit is located in a preset area of the second wiring sub-layer, and the preset area is the area of the second wiring sub-layer where the second end is not provided; The electronic device further includes a printed circuit board, and the flexible circuit board unit is connected to the printed circuit board.

22. The electronic device according to claim 21, characterized in that, The printed circuit board includes a main board and a sub-board, and the main board is connected to the sub-board through the flexible circuit board unit.

23. The electronic device according to claim 21, characterized in that, The electronic device further includes a functional device, and the functional device is connected to the printed circuit board through the flexible circuit board unit.

24. The electronic device according to claim 23, wherein The functional device includes a speaker or a SIM card.

25. The electronic device according to claim 21, wherein The flexible circuit board unit is configured as an NFC coil.

26. The electronic device according to any one of claims 20-25, characterized in that, The electronic device includes a wireless charging receiving device or a wireless charging transmitting device.

27. A wireless charging system, characterized in that, It includes: The electronic device according to any one of claims 20 - 26.

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